Recently, due to the wide spread use of the Internet, it has been common to provide geographic information converted to a digital form. Typical examples of digitalized geographic information may include online map services, car navigation systems, etc. As such, one of benefits of the digitalized geographic information is to provide a variety of convenient functions for users through user interfaces capable of allowing the users to retrieve desired geographic information. Further, changes in the geographic information may be easily updated through remote updating services, etc., so that, in the aspect of latest geographic information, such digital data may be predominant over conventional printed materials.
It has been conventionally common for service providers to combine digital maps generated by the addition of simple symbols with search interfaces and then to provide the combined digital maps, but since there are apparent differences between information of areas displayed on the digital map and real information of the areas, it is difficult to identify the real information of the areas from the digital map.
Filed on Nov. 8, 2007 and disclosed on Jun. 19, 2008, as an attempt to solve such a problem, US Laid-Open Publication No. 2008-143727 relates to a technology for providing a panoramic image(s) relating to a certain place such as a bystreet, a road, etc. appearing on the digital map and, if a user selects a specific pixel with an arrow, etc. on the panoramic image, offering data of a different panoramic image(s) corresponding to a place shown at the specific pixel. Accordingly, the user may identify real information of the certain place on the digital map and get another panoramic image which expresses geographic information on the certain place shown on the panoramic image the user is now referring to in more details through a link between panoramic images.
Further, a conventional technology for performing visual search by using a panoramic image(s) has been introduced. According to the technology, by referring to a queried image inputted by a user, it may retrieve an appropriate panoramic image including what is similar to an object included in the queried image among multiple panoramic images and provide the appropriate panoramic image to the user.
According to the conventional technology for performing the visual search by using the panoramic image(s), a digital map service capable of maximizing user convenience is available. More specifically, if a user inputs an image including a building as a query even without knowing an actual location of the building, it is possible to retrieve, and provide for the user, a panoramic image(s) which actually includes the building or its (or their) relevant information.
According to the conventional technology for performing the visual search by using the panoramic image(s), since buildings look similar and most of them have consistently repeated patterns, if an image of a specific building is inputted as a query, the retrieval speed becomes excessively low and it its not easy to retrieve an appropriate panoramic image(s) including what is accurately matched with the specific building.